Cardiac rhythm management devices such as pacemakers, cardioverter/defibrillators, and combination devices typically include numerous program parameters that affect device function, including arrhythmia detection and therapy delivery. Device function can be adjusted to meet the needs of a patient by changing the program parameters. Some examples of program parameters include tachy mode (for detecting and providing therapy for tachycardia) and brady mode (for detecting and providing therapy for bradycardia). Changing program parameters such as tachy mode and/or brady mode activates or deactivates major cardiac analysis and therapy functions of the device.
Most program parameters are adjusted using an external programmer recorder/monitor that communicates with the implanted device via wireless telemetry through the skin. Program parameters may be turned on or off through the use of the external programmer. Other mechanisms may also modify parameter programming. For example, the device may, upon detection of an exhausted battery condition, disable some device functions rather than delivery compromised therapy that may be erratic or potentially dangerous. Some devices respond to the presence of a magnet by inhibiting therapy momentarily, or permanently via magnet maneuvers. Robust device designs perform periodic system integrity validation including program parameters. The device may alter programming to correct integrity errors. These types of changes to the program parameters may have a profound effect on the overall operation of the implanted device.
When a patient visits their physician for routine periodic device follow-ups, the device is interrogated using the external programmer recorder/monitor. During this interrogation, a review is made of parameter programming to assure that the device settings are appropriate for the patient cardiac condition. When parameters are not as expected (e.g., a program parameter has been turned off, or there is an alteration in programmable values the program parameter is using), the clinician must investigate to discover how and why this occurred and take corrective action. Knowing why and when the parameter programming changed is important information to assess the situation. When this information is limited or incomplete, it places doubt on the assessment and the reliability of the device. Therefore, a need exists for understanding how and why parameter programs have been affected during the operation of a cardiac rhythm management device.